The main goal of the study was to reduce blood-sugar levels to 6 per cent or less as recommended by the American Diabetes Association. The study measured those who achieved the levels of 6 or less per cent after one year.

The scientists found that only 12% (5 of 41 patients) of people who took most advanced medical treatments were able to control their blood-sugar levels as against 42% (21 of 50 patients) people who underwent gastric-bypass surgery and 37% (18 of 49 patients) people who had sleeve-gastrectomy surgery.

The scientists found the changes in body weight were greater in patients who had gastric bypass surgery and sleeve gastrectomy surgery than patients who had medical therapy.

"Within days and hours of surgery, before there's any measurable weight loss, we saw dramatic changes. A majority of patients who had surgery left the hospital with normal blood sugars. However, this was not as effective for people who had diabetes for many years," Reuters quoted Dr Philip Schauer, director of Bariatric and Metabolic Institute at the Cleveland Clinic, who led the clinical trial as saying.

The study was presented at the annual scientific sessions of the American College of Cardiology in Chicago and has been published in the New England Journal of Medicine.